Klei Thomas R L, Meinderts Sanne M, van den Berg Timo K, van Bruggen Robin
Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory, University of Amsterdam , Amsterdam , Netherlands.
Front Immunol. 2017 Feb 2;8:73. doi: 10.3389/fimmu.2017.00073. eCollection 2017.
Erythropoiesis is a highly regulated process where sequential events ensure the proper differentiation of hematopoietic stem cells into, ultimately, red blood cells (RBCs). Macrophages in the bone marrow play an important role in hematopoiesis by providing signals that induce differentiation and proliferation of the earliest committed erythroid progenitors. Subsequent differentiation toward the erythroblast stage is accompanied by the formation of so-called erythroblastic islands where a central macrophage provides further cues to induce erythroblast differentiation, expansion, and hemoglobinization. Finally, erythroblasts extrude their nuclei that are phagocytosed by macrophages whereas the reticulocytes are released into the circulation. While in circulation, RBCs slowly accumulate damage that is repaired by macrophages of the spleen. Finally, after 120 days of circulation, senescent RBCs are removed from the circulation by splenic and liver macrophages. Macrophages are thus important for RBCs throughout their lifespan. Finally, in a range of diseases, the delicate interplay between macrophages and both developing and mature RBCs is disturbed. Here, we review the current knowledge on the contribution of macrophages to erythropoiesis and erythrophagocytosis in health and disease.
红细胞生成是一个受到高度调控的过程，一系列连续事件确保造血干细胞最终正确分化为红细胞（RBCs）。骨髓中的巨噬细胞通过提供诱导最早定向红细胞祖细胞分化和增殖的信号，在造血过程中发挥重要作用。随后向成红细胞阶段的分化伴随着所谓成红细胞岛的形成，其中央巨噬细胞提供进一步的信号，诱导成红细胞分化、扩增和血红蛋白化。最后，成红细胞排出其细胞核，细胞核被巨噬细胞吞噬，而网织红细胞则释放到循环中。在循环过程中，红细胞会缓慢累积损伤，这些损伤由脾脏的巨噬细胞修复。最后，在循环120天后，衰老的红细胞被脾脏和肝脏的巨噬细胞从循环中清除。因此，巨噬细胞在红细胞的整个生命周期中都很重要。最后，在一系列疾病中，巨噬细胞与发育中和成熟红细胞之间微妙的相互作用会受到干扰。在此，我们综述了目前关于巨噬细胞在健康和疾病状态下对红细胞生成和红细胞吞噬作用贡献的相关知识。
